AR150 hissing sound

I can hear hissing sound from my router. The heavier the router load, the louder the sound. I think the noise is from the coil in 5V to 3.3V DCDC converter. Can someone tell me the capacity of the inductor and which one is it? I have tools and can replace it myself.

This is the first time we have received such feedback. Could you please return the device to us for analysis?

Check the wall-plug adapter - some USB PSU’s might be less than optimal, and introduce noise on to the DC bus into the AR150. The “hissing” you hear is coil-whine

It’s harmless enough - but with more than 40 ar150’s fielded, I honestly have not seen anything resembling noises like you’ve mentioned.

I’m hearing a sound I’d also describe as hissing from a MIFI. My concern is it might have something to do with the battery. Anyone ever have one do this?

The hissing on the Mifi is normal, its coming from the battery charging circuit, specifically the coil at the frequency the switching regulator is running at :slight_smile: